How to determine tread on tires

How to Check Your Tire Tread Depth at Home

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Jun 15, 2020

Do you need new tires? Are you unsure? There is an extremely simple way to check your tire tread depth at home with no special tools! All you need is a quarter and a penny to get started.

Before using the coin, you check your tires for the “wear indicators” as seen in the video above. Look for these rubber notches between the tread of your tires. They are raised to 2/32 of an inch and will tell you when your tires are completely worn to an unsafe level. Once the indicator is flush with the tread, that means it’s time to replace your tires right away.

If your tires do not have these indicators, or if you want to be proactive and get an idea of how much tread you have left before it’s too late, it’s time to use your coins. First, grab your quarter. Insert it in the space between your tire tread, with George Washington’s head facing down. If your tread surpasses the top his head, you are above 4/32 of an inch and are in good shape. Once the tread comes flush with the top of Washington’s head, that means you are at 4/32 of an inch. While still safe, it’s time to start planning ahead. Depending on how much you drive and on what terrain, you’ll need to replace your tires soon.

If you find that your tread is not even touching Washington’s head, you can grab your penny. Insert the penny in the same way, with Lincoln’s head facing down. When your tread is flush with the top of Lincoln’s head that means you are at 2/32 of an inch. As with the wear indicator, this means it’s time to replace your tires. Regardless of season, low tread is unsafe, reducing traction, increasing stopping distance and increasing chances of getting a flat.

Other Considerations

Make sure you check your tread on all four tires and in more than one spot. If you find that the center of your tires is wearing more than the outer edges, your tire is likely over inflated. On the other hand, if the edges are wearing more quickly than the center, your tires are likely under inflated. When certain tires are wear more quickly than others, you might need a tire rotation or alignment. In this case, we’d be happy to help you figure out what needs done to ensure even wear to not only increase the lifespan of your tires, but also keep you driving safely!

If you do need new tires, take advantage of our $70 rebate on a set of four eligible tires though July 31, 2020! Start shopping new tires here.

Tags: Colorado, Longmont, new tires, Nissan, tire tread, tires, tread depth
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How to Check Tire Tread Depth: The Penny Test

When it comes to checking tire tread, there are a number of methods that can help you know if it’s time to replace a tire. Heavily worn tread will prevent a tire from performing as designed and can lead to unsafe driving conditions. One of the simplest, most common ways to check tread depth requires nothing more than a penny and a few moments of your time.


In the United States, tire tread depth is measured in 32nds of an inch. New tires typically come with 10/32” or 11/32” tread depths, and some truck, SUV and winter tires may have deeper tread depths than other models. The U.S. Department of Transportation recommends replacing tires when they reach 2/32”, and many states legally require tires to be replaced at this depth.

The idea of the penny test is to check whether you’ve hit the 2/32” threshold. Here’s how it works:

    Place a penny between the tread ribs on your tire. A “rib” refers to the raised portion of tread that spans the circumference of your tire. Tire tread is composed of several ribs.

    Turn the penny so that Lincoln’s head points down into the tread.

    See if the top of his head disappears between the ribs. If it does, your tread is still above 2/32” , If you can see his entire head, it may be time to replace the tire because your tread is no longer deep enough.

    When performing the penny tire test, remember not only to check each tire, but to check various places around each tire. Pay special attention to areas that look the most worn. Even if parts of your tread are deeper than 2/32”, you should still replace the tire when any areas fail the penny test.

    Consistent wear around the whole tire is normal, but uneven tread wear could be a sign of improper inflation, wheel misalignment, or a variety of other things. If you see uneven tread wear, you should have a technician inspect your vehicle.



    A simple way to check your tire tread depth is by using a tread depth gauge. You can find tire tread depth gauges at your local auto parts store. There are many models available, but an inexpensive simple graduated probe gauge will work just fine. All you have to do is stick the probe into a groove in the tread and press the shoulders of the probe flat against the tread block and read the result. All gauges should measure in both 32nds of an inch and millimeters.


    Another indicator of worn out tread already lives in your tires themselves. Every performance, light truck, or medium commercial tire comes equipped with indicator bars (or wear bars) embedded between the tread ribs at 2/32”. They’re there to help you monitor tread depth and make decisions about tire replacement. Just look to see if the tread is flush with the indicator bars. If they are, it’s time to replace the tire.


    While the penny tire test does deliver on what it promises – indicating whether tread has reached the legal limit – it may not be the best indicator of whether your tires are safe for the road. Tire performance can diminish significantly before your tread hits 2/32”. Even though the law deems fit for safe driving may not prevent you from hydroplaning or losing control in rainy, slushy conditions. If you think your tires may be close to needing replacement, have them checked out by a licensed mechanic.

    How to determine the wear of summer tires

    In fact, the average life of any tire is 5-7 years, but a lot depends on how the owner treats his car. Aggressive driving, improper seasonal tire storage, unrepaired suspension/balancing problems, incorrect pressure and other errors can significantly shorten tire life. But worn tires can be a serious problem on the road: an increased risk of uncontrolled skidding, hydroplaning, even accidents is the price that drivers and passengers have to pay for using old tires.

    Tire wear index

    Each manufacturer indicates the so-called wear index on the tire profile, which most often looks like the inscription “Treadwear 100” and means a maximum of 48,000 km on a standard road surface (polygon). In a real environment and often not the most ideal roads, this number actually needs to be divided by 1.5 - we get 36,000 km.

    By analogy, if the wear resistance index is 150, then this means “factory” 72 thousand km, 200 - 96 thousand km., and so on.

    What are the dangers of worn tires on the road:

    • grip with the roadway deteriorates, which leads to an increased likelihood of skidding, accidents, hydroplaning in case of rainy weather;

    • reduced cross-country ability in off-road conditions;

    • increases the risk of a tire puncture while driving.

    It is also worth remembering that the issue of tire wear is regulated by traffic rules, and you can get a fine for using “bald” rubber. Knowing what maximum tire wear is acceptable, this is easy to avoid: 1.5-2 mm for summer, and 4-5 mm for winter (a more accurate figure is indicated by the manufacturer).

    3 ways to determine tire wear

    1. According to the wear indicator on the tire. To find this indicator, you need to inspect the side of the tire and find one of the markings: a triangle, a company logo, a snowflake, or the abbreviation TWI. If the tread has worn down to this indicator, it means that the tire needs to be disposed of urgently.

    2. Many people in the old fashioned way prefer to use a 10-kopeck coin. Insert it into the tread with the inscription "10 kopecks" towards you, and if it is visible, the wear level is too high, you need to replace the tire. This method is convenient, but not entirely accurate: by measuring wear in different parts of the tire in this way, it will be difficult to estimate its unevenness by eye, and this is also an extremely important indicator.

    3. It is optimal to use a special gauge, depth ruler or caliper for these purposes. This will allow you to measure the wear of the tread in different parts of the tire with an accuracy of up to a millimeter and understand if there is uneven wear.

    Uneven tire wear: how to determine the causes, what is dangerous

    If measurements show different results in different parts of the tread, it is important to determine exactly how your tires wear in order to understand where and what the operating error is.

    If the tread wears more on the sides and the center wears off less, this means that the tire pressure is insufficient and the contact patch with the road is not correct. This leads not only to poor vehicle stability, but also to increased fuel consumption.

    If the tread is worn down the middle but the sides are fine, your tires are overinflated. Sometimes this is done intentionally in order to save fuel, but in this case, the tires will still have to be changed ahead of schedule.

    There is also a possibility of increased wear on the inside or outside of the tread - this indicates an incorrect camber. A visual table with wear options and their causes:

    How to assess tire wear visually: additional parameters

    • Cracks on the sides of tires can indicate frequent off-road driving, improper storage, low-quality rubber or long service life, as well as incorrect tire pressure.

    • Bulges or "hernias" on the sides of the tires appear as a result of the side part hitting hard obstacles. Tires with such damage are not recommended.

    • Dents on the tread indicate insufficient depreciation and unadjusted camber. Having found such damage, it is necessary to drive the car to the service and make sure that the suspension is in good condition.

    • Individual wear spots on the tread indicate aggressive driving / braking, skidding with wheel locks, or prolonged parking of the car in one position.

    How to calculate tire wear percentage

    Most often, this is required for the sale and purchase of used tires in order to orient the buyer in the degree of their wear. Many sellers give this figure at random, but this method has nothing to do with the actual assessment of the degree of tire wear. It is also important to understand that a conditional 50% wear for a summer tire is an acceptable value, while 50% wear of a winter tire tread is a sign that the tire cannot be used. Therefore, it is important to know how to accurately determine the percentage of tire wear so as not to get into an unpleasant situation.

    Many people divide the actual tread height by the height of the same, but new tire, and get a certain percentage of wear. This would be correct, if not for one BUT: we cannot physically erase the tread to zero, and the law prohibits the use of tires with a tread below the permitted values.

    You can calculate actual tire wear by dividing the difference between the new tire height and the actual tire height by the difference between the new tire tread height and the minimum possible tread height for that tire, and then multiplying this number by 100.

    If it is impossible to find out the height of the same, but with a new tire, use the average values ​​​​of your tire type:

    Tire type

    Average tread height at start of use

    Winter tires with Scandinavian tread

    10 mm

    Winter with regular or asymmetric tread

    9 mm

    High-speed winter

    7 mm

    Summer tires with classic tread

    8 mm

    Summer speed

    7 mm

    You can check summer tires for wear a little less often than winter tires, since in summer the tread depth is not so important for patency.

    If you have assessed the condition of your tires on all of the above factors and realized that the tires are worn out, be sure to replace them with new ones as soon as possible.

    View tire catalog

    safe tread height, traffic regulations

    The tire tread is the outer part of the wheel that provides traction in all weather conditions. The protectors inevitably wear out during the operation of the car, the working height of the slope decreases. The residual tread depth should be periodically monitored and the set of tires should be renewed in time - this will reduce the risk of losing control of the car and save the car owner from fines from the traffic police.

    Tread wear rate depends on many factors:

    Measuring the thickness of the tread layer will allow you to accurately determine the degree of tire wear and make a decision in time to replace them with new ones.

    Different tires have different wear limits. Tread depth affects vehicle handling and road safety.

    According to Chapter 5 of the SDA, limiting norms for the height of the tread pattern have been established. For category M1 - passenger cars - as well as vehicles of categories N1, O1 and O2, the minimum allowable value is 1.6 mm. When using winter tires on snowy or icy surfaces - the limit is 4 mm.

    Let's explain what categories of vehicles we are talking about:

    • N1 - vehicles intended for the carriage of goods, having a technically permissible maximum mass of not more than 3.5 tons;

    • O1 - trailers, the technically permissible maximum mass of which is not more than 0.75 tons;

    • O2 - trailers, the technically permissible maximum weight of which is over 0.75 tons, but not more than 3.5 tons.

    The traffic police officer has the right to measure the residual depth with a verified device. In case of a recorded violation, a fine is imposed on the car owner.

    The new summer tire has an average tread depth of 7-8 mm. The service life of summer tires is usually 3-5 seasons with average mileage and moderate driving style.

    Residual height limitation by law is 1.6 mm. However, with a remaining outer layer of 3 mm, the machine is already difficult to control, grip deteriorates, and a safety hazard arises.

    Do not wait until the critical value is reached. Make sure you change tires in advance.

    Winter tires are used in severe weather conditions: low temperatures, icy conditions, on snowy road surfaces. Worn elements make the tire ineffective on slippery winter roads. Accordingly, a more serious approach to the condition of the tire tread is needed.

    Non-studded friction tire (Velcro) with a tread depth of 8-9mm. A new studded model - from 9 to 11 mm, some firms produce a tread with a height of 12-18 mm.

    If the tread wear is up to 4-5 mm, the winter set of tires needs to be replaced. In addition, the loss of more than 50% of the metal spikes is also a reason to change the car's shoes.

    The average life of winter tires is 2-4 years.

    Universal all-weather is used in a temperate climate both in winter and in summer, it is optimal at temperatures from +10 to -10˚C. This type of tire is not suitable for use in snowfall or severe frosts. SDA allows the use of all-season tires in the winter if there is a special marking:

    All-season tires last 3-4 years on average. In summer, at high temperatures, all-weather tires wear out much faster. It is recommended to buy new tires when the tread layer is abraded to a value of 2-2.5 mm.

    You can estimate the remaining tread layer in various ways:

    1. On some tire models there are special volumetric indicators in the form of jumpers. Check: if the tread layer is worn down to the level of the jumpers, the tire is not suitable for further use.

    2. On the surface of certain types of tires, manufacturers knock out numbers of various depths. Depreciation is assessed visually - by the visibility of individual numbers.

    3. With the help of measuring instruments: from a metal ruler, caliper, depth gauge to an electronic tread depth gauge.

    Many motorists measure the remaining tread depth with a coin. Warning: this method of measurement is not accurate. It will not show you actual tire wear figures.

    Tire tread height should be measured at least at 6 different points, preferably at 9 or even 12: in the center and from both edges of the tread, at different points around the circumference of the tire. The measurement results at all specified points must match. If they do not match, then the tire wears unevenly. The driver should find out why this is happening. Some causes of uneven tire wear are low or high pressure in them relative to the regular one, suspension failure, extreme driving style.

    Old tires have become unusable, the amount of tread remaining is approaching a critical line - no need to take risks, it's time to change your car's shoes. There is a great temptation to get by with small financial costs and purchase a set of used tires. Be careful!

    Sellers advertise used tires in good or excellent condition. Do not be too lazy to personally measure the height of the tread layer. And remember: for winter tires, a residual tread depth of 4 mm is already 100% wear.

    When buying used tires with tires, it is important to remember that tires of different manufacturers and seasonality initially have different tread heights (when they are new). And most importantly: the tires have, accordingly, different wear limits - the tread depth at which the tire begins to lose important characteristics. These differences are most noticeable in winter and summer tires. Keep these points in mind when measuring the remaining tread depth of used tires.

    The quality of domestic roads, unfortunately, does not allow tires to be used for 7–10 years. If you still decide to buy a used kit, check the year of manufacture - it is better not to consider tires older than 8 years.